1. Field of the Invention
The invention concerns a packaging unit for a liquid or semiliquid product, preferably one capable of flowing under gravity. The invention is particularly suitable for readily oxidizable products of the type used in the field of hair care, such as reducing agents or coloring products.
2. Description of the Related Art
Such products are typically packaged in thermoplastic boat-shaped receptacles, having one or several compartments containing the product. The compartments are obturated in a leakproof manner by a removable cover which is generally heat sealed. Because of the highly oxidizable nature of certain products, such as those used in the field of hair care, it is necessary to fill the compartment (or compartments) to the top so that there is substantially no space between the free surface of the product and the cover. One of the problems associated with such packaging units relates to the fact that when tearing off the cover to allow access to the product, a portion of the product escapes from the compartment which, apart from the wastage of the product, produces stains, in particular on the hands of the user. Such a packaging unit is described for example in European Patent No. 206 583. The packaging unit there described takes the form of a compartmentalized container in which each compartment is closed by an individual sealing foil.
French Patent No. 2 451 322 describes a boat-shaped food receptacle with a rolled edge, having several compartments closed by a single stretched foil fixed to the rolled edge and forming a cover. The separating partitions between two contiguous compartments progressively rise from one edge in an arc in order to increase the tension of the foil forming the cover. A groove-shaped fillet is disposed in the zones between two contiguous compartments so as to retain the product particles which pass under the cover, in particular during transport, thus forming a leakproof seal between two contiguous compartments once they have been filled. Because of the localized disposition of the fillet or fillets (which is limited to the zones separating the edges common to two contiguous compartments), this arrangement does not resolve the problem mentioned above to the extent that the spattering of the product is not limited to these zones between two contiguous compartments. Moreover, the fillet is not separated from the product inside the compartments, so the groove can be completely filled during transport of the packaging unit, which renders it ineffectual when the tensioned foil is opened. In fact, once filled, the groove can no longer recover in any substantial way the product which may escape when the foil forming the cover is torn away. Moreover, after opening, the product contained in the groove situated between two contiguous compartments remains there, which poses problems when the consumer wishes to recover it. In practice, the product is "lost."
French Patent No. 2 447 322 describes a boat-shaped receptacle for food products, having several compartments covered by a single film. To increase the rigidity of the unit, a stamped recess is made in each of the corners of the receptacle. As in the preceding document, in the closed position of the receptacle, the recesses are not separated from the product (or products) contained in the various compartments.
German Patent No. 3 843 861 describes a thermoformed container fitted with a spout delimited by two hollows situated on either side of the spout, and whose presence only seems justified by the constraints of making the spout by thermoforming.
U.S. Pat. No. 4,863,036 describes a tub for a small dose of cream or milk, on the edge of which there has been provided a small raised tube situated above the filling level and communicating with the container. The combination in two stages of this small tube and an opening of a heat-sealed cover mainly allows the easy dispensing of the product via a small opening. Such a device is particularly unsuitable for the packaging of hair care products such as those mentioned above.
WO-94/27868 and U.S. Pat. No. 2,745,752 describe packaging units of the boat-shaped type with one or several compartments, used for the packaging of meat, butter or other food products of the same type. According to some embodiments, the compartment or compartments are surrounded by a channel whose function is to allow the cover to be cut all around the receptacle when a blade is inserted in the channel at the time of cutting the cover. The teachings of these documents do not resolve the problem of collecting the product which can escape from the compartments, either at the time of their opening or during the manipulation of the packaging unit after opening. Because of the nature of the packaged products, the above problem does not arise. Moreover, to permit the cutting described in these documents, a groove only slightly wider than the width of the blade and of an adequate depth is sufficient.